1. Field of the Inventions
The present inventions relate to an action control device for a small boat having a propulsion unit such as, for example, an outboard motor and a stern drive.
2. Description of the Related Art
For example, Japanese Patent Document JP-B-2959044 discloses a boat having an electrically operated steering unit which is designed to provide smooth steering movement of the associated outboard motor. Japanese Patent Document JP-A-Hei 10-310074 discloses another steering device by which a force used to cause a pivotal movement of the propulsion unit of the outboard motor can be adjusted in response to running conditions, allowing the steering operation to be made with less force. Under a normal steering condition such as when a water surface is calm, it is preferable that such a power steering unit, which is operated electrically, provides a light steering force.
On the other hand, when a small boat encounters large waves, strong wind or the like, a position and/or orientation of the boat can change quickly. Consequently, the running resistance (e.g., the hydrodynamic resistance against the movement of the hull) and bilateral balance of the boat vary, which can make the riders of the boat uncomfortable. Quick steering adjustments can be used to counteract the external forces caused by the waves and wind and thus can reduce or inhibit listing (leaning) of the hull or other movements that can make the riders of the boat uncomfortable.
However, in some environments of use, such as fishing for example, the operator of the boat is normally stands near the steering wheel while operating the boat, in contrast to the position of a driver's seated position while driving a car. When such a boat rolls and bounces in rough water due to waves and/or strong wind, operators stand can become tired by continuously shifting their balance to compensate for the rolling and bouncing. Additionally, it can be difficult for an operator to quickly and accurately counteract the forces caused by the waves and wind.
In the art of land vehicles, Japanese Patent Document JP-A-2004-155282 discloses a steering unit which detects a drive condition of land vehicle such as, for example, a vehicle speed and a magnitude of acceleration and provides a drive environment in response to the detected values. Conventionally, however, no such means are available for assisting the steering operation of a boat by detecting an action of the boat.